Soil degradation occurs when key soil attributes for plant growth or ecosystem functionality deteriorate.
To combat this, the United Nations funded a project to produce a global view of soil quality called Global Assessment of Land Degradation and Improvement (GLADA). Through the research conducted by GLADA, the UN was able to identify areas in the world that were improving or worsening.
One of the key areas looked at was topsoil. Topsoil is lost through erosion. This can happen when vegetative cover is removed. Eroding soil is called sediment. Topsoil erosion can destroy habitats. Water erosion can change soil composition over time, leading to hardening of the soil and dryness and creating a crust that stops further erosion but also prevents water from passing through or seeds from taking root.
Soils are most affected by agriculture and mining. Some agricultural practices such as center-pivot irrigation, drip irrigation and no-till agriculture have met with great success in terms of maintaining topsoil. However, they come with side effects such as salinization where there are too many salts in the soil and plant growth is suppressed, and leaching where soils lose nutrients that flow right out of the soil.
Mining is big business. Mining involves pulling out metals, salts and other materials out of the earth to make goods and services. Mining removes vegetation and impacts human health, water quality and results in soil erosion.